Downlink Radio Resource Control Message Transmission in 2-Step Random Access

ABSTRACT

Apparatuses, systems, and methods for a wireless device to perform 2-step random access procedures. The disclosure identifies techniques for transmitting and receiving downlink connection configuration information, such as a radio resource control message, in a 2-step random access procedure.

PRIORITY CLAIM

This application claims priority to Chinese patent application serialnumber 201910745594.1, entitled “Downlink Radio Resource Control MessageTransmission in 2-Step Random Access,” filed Aug. 13, 2019, which ishereby incorporated by reference in its entirety as though fully andcompletely set forth herein.

FIELD

The present application relates to wireless devices, and moreparticularly to apparatus, systems, and methods for performing 2-steprandom access.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Further,wireless communication technology has evolved from voice-onlycommunications to also include the transmission of data, such asInternet and multimedia content. Random access procedures may typicallyinclude four messages (e.g., four steps, e.g., 4-step RA or 4-stepRACH). Techniques for random access with two messages (e.g., 2-stepRACH) are in development, however improvements in the field are desired.

SUMMARY

Embodiments relate to apparatuses, systems, and methods to performtransmission of downlink radio resource control (RRC) messages incontext of a 2-step random access (RA) procedure, e.g., an RA procedureusing two messages (e.g., two steps, e.g., instead of previous four stepprocesses). Embodiments include techniques for transmitting a firstdownlink RRC message from a network to a wireless device. In someembodiments, the RRC message may be transmitted via a unicast (e.g.,dedicated) transmission. In some embodiments, the RRC message may betransmitted via a group-cast transmission.

This Summary is intended to provide a brief overview of some of thesubject matter described in this document. Accordingly, it will beappreciated that the above-described features are merely examples andshould not be construed to narrow the scope or spirit of the subjectmatter described herein in any way. Other features, aspects, andadvantages of the subject matter described herein will become apparentfrom the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtainedwhen the following detailed description of various embodiments isconsidered in conjunction with the following drawings, in which:

FIG. 1 illustrates an example wireless communication system, accordingto some embodiments;

FIG. 2 illustrates a base station (BS) in communication with a userequipment (UE) device, according to some embodiments;

FIG. 3 illustrates an example block diagram of a UE, according to someembodiments;

FIG. 4 illustrates an example block diagram of a BS, according to someembodiments:

FIG. 5 illustrates an example block diagram of cellular communicationcircuitry, according to some embodiments:

FIGS. 6 and 7 illustrate examples of a 5G NR base station (gNB),according to some embodiments;

FIG. 8 illustrates techniques for transmitting a radio resource controlmessage in the context of 2-step random access, according to someembodiments;

FIG. 9 illustrates aspects of an exemplary 4-step random accessprocedure, according to some embodiments;

FIGS. 10 and 11 illustrate aspects of an exemplary 2-step random accessprocedure, according to some embodiments;

FIGS. 12 and 13 illustrate aspects of transmitting a radio resourcecontrol message using a dedicated transmission, according to someembodiments; and

FIGS. 14-18 illustrate aspects of transmitting a radio resource controlmessage using a group-cast transmission, according to some embodiments.

While the features described herein may be susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and are herein described indetail. It should be understood, however, that the drawings and detaileddescription thereto are not intended to be limiting to the particularform disclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the subject matter as defined by the appended claims.

DETAILED DESCRIPTION Terms

The following is a glossary of terms used in this disclosure:

Memory Medium—Any of various types of non-transitory memory devices orstorage devices. The term “memory medium” is intended to include aninstallation medium, e.g., a CD-ROM, floppy disks, or tape device; acomputer system memory or random access memory such as DRAM, DDR RAM,SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash,magnetic media, e.g., a hard drive, or optical storage; registers, orother similar types of memory elements, etc. The memory medium mayinclude other types of non-transitory memory as well or combinationsthereof. In addition, the memory medium may be located in a firstcomputer system in which the programs are executed, or may be located ina second different computer system which connects to the first computersystem over a network, such as the Internet. In the latter instance, thesecond computer system may provide program instructions to the firstcomputer for execution. The term “memory medium” may include two or morememory mediums which may reside in different locations, e.g., indifferent computer systems that are connected over a network. The memorymedium may store program instructions (e.g., embodied as computerprograms) that may be executed by one or more processors.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems devices which are mobile or portable and which performs wirelesscommunications. Examples of UE devices include mobile telephones orsmart phones (e.g., iPhone™ Android™-based phones), portable gamingdevices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™,iPhone™), laptops, wearable devices (e.g. smart watch, smart glasses),PDAs, portable Internet devices, music players, data storage devices, orother handheld devices, etc. In general, the term “UE” or “UE device”can be broadly defined to encompass any electronic, computing, and/ortelecommunications device (or combination of devices) which is easilytransported by a user and capable of wireless communication.

Wireless Device—any of various types of computer system devices whichperforms wireless communications. A wireless device can be portable (ormobile) or may be stationary or fixed at a certain location. A UE is anexample of a wireless device.

Communication Device—any of various types of computer systems or devicesthat perform communications, where the communications can be wired orwireless. A communication device can be portable (or mobile) or may bestationary or fixed at a certain location. A wireless device is anexample of a communication device. A UE is another example of acommunication device.

Base Station—The term “Base Station” has the full breadth of itsordinary meaning, and at least includes a wireless communication stationinstalled at a fixed location and used to communicate as part of awireless telephone system or radio system.

Processing Element—refers to various elements or combinations ofelements that are capable of performing a function in a device, such asa user equipment or a cellular network device. Processing elements mayinclude, for example: processors and associated memory, portions orcircuits of individual processor cores, entire processor cores,processor arrays, circuits such as an ASIC (Application SpecificIntegrated Circuit), programmable hardware elements such as a fieldprogrammable gate array (FPGA), as well any of various combinations ofthe above.

Channel—a medium used to convey information from a sender (transmitter)to a receiver. It should be noted that since characteristics of the term“channel” may differ according to different wireless protocols, the term“channel” as used herein may be considered as being used in a mannerthat is consistent with the standard of the type of device withreference to which the term is used. In some standards, channel widthsmay be variable (e.g., depending on device capability, band conditions,etc.). For example, LTE may support scalable channel bandwidths from 1.4MHz to 20 MHz. In contrast, WLAN channels may be 22 MHz wide whileBluetooth channels may be 1 Mhz wide. Other protocols and standards mayinclude different definitions of channels. Furthermore, some standardsmay define and use multiple types of channels, e.g., different channelsfor uplink or downlink and/or different channels for different uses suchas data, control information, etc.

Band—The term “band” has the full breadth of its ordinary meaning, andat least includes a section of spectrum (e.g., radio frequency spectrum)in which channels are used or set aside for the same purpose.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thus,the term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

Approximately—refers to a value that is almost correct or exact. Forexample, approximately may refer to a value that is within 1 to 10percent of the exact (or desired) value. It should be noted, however,that the actual threshold value (or tolerance) may be applicationdependent. For example, in some embodiments, “approximately” may meanwithin 0.1% of some specified or desired value, while in various otherembodiments, the threshold may be, for example, 2%, 3%, 5%, and soforth, as desired or as required by the particular application.

Concurrent—refers to parallel execution or performance, where tasks,processes, or programs are performed in an at least partiallyoverlapping manner. For example, concurrency may be implemented using“strong” or strict parallelism, where tasks are performed (at leastpartially) in parallel on respective computational elements, or using“weak parallelism”, where the tasks are performed in an interleavedmanner, e.g., by time multiplexing of execution threads.

Configured to—Various components may be described as “configured to”perform a task or tasks. In such contexts, “configured to” is a broadrecitation generally meaning “having structure that” performs the taskor tasks during operation. As such, the component can be configured toperform the task even when the component is not currently performingthat task (e.g., a set of electrical conductors may be configured toelectrically connect a module to another module, even when the twomodules are not connected). In some contexts, “configured to” may be abroad recitation of structure generally meaning “having circuitry that”performs the task or tasks during operation. As such, the component canbe configured to perform the task even when the component is notcurrently on. In general, the circuitry that forms the structurecorresponding to “configured to” may include hardware circuits.

Various components may be described as performing a task or tasks, forconvenience in the description. Such descriptions should be interpretedas including the phrase “configured to.” Reciting a component that isconfigured to perform one or more tasks is expressly intended not toinvoke 35 U.S.C. § 112(f) interpretation for that component.

FIGS. 1 and 2—Communication System

FIG. 1 illustrates a simplified example wireless communication system,according to some embodiments. It is noted that the system of FIG. 1 ismerely one example of a possible system, and that features of thisdisclosure may be implemented in any of various systems, as desired.

As shown, the example wireless communication system includes a basestation 102 which communicates over a transmission medium with one ormore user devices 106A, 106B, etc., through 106N. Each of the userdevices may be referred to herein as a “user equipment” (UE). Thus, theuser devices 106 are referred to as UEs or UE devices.

The base station (BS) 102 may be a base transceiver station (BTS) orcell site (a “cellular base station”), and may include hardware thatenables wireless communication with the UEs 106A through 106N.

The communication area (or coverage area) of the base station may bereferred to as a “cell.” The base station 102 and the UEs 106 may beconfigured to communicate over the transmission medium using any ofvarious radio access technologies (RATs), also referred to as wirelesscommunication technologies, or telecommunication standards, such as GSM,UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces),LTE, LTE-Advanced (LTE-A), 5G new radio (5G NR), HSPA, 3GPP2 CDMA2000(e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD), etc. Note that if the base station102 is implemented in the context of LTE, it may alternately be referredto as an ‘eNodeB’ or ‘eNB’. Note that if the base station 102 isimplemented in the context of 5G NR, it may alternately be referred toas ‘gNodeB’ or ‘gNB’.

As shown, the base station 102 may also be equipped to communicate witha network 100 (e.g., a core network of a cellular service provider, atelecommunication network such as a public switched telephone network(PSTN), and/or the Internet, among various possibilities). Thus, thebase station 102 may facilitate communication between the user devicesand/or between the user devices and the network 100. In particular, thecellular base station 102 may provide UEs 106 with varioustelecommunication capabilities, such as voice, SMS and/or data services.

Base station 102 and other similar base stations operating according tothe same or a different cellular communication standard may thus beprovided as a network of cells, which may provide continuous or nearlycontinuous overlapping service to UEs 106A-N and similar devices over ageographic area via one or more cellular communication standards.

Thus, while base station 102 may act as a “serving cell” for UEs 106A-Nas illustrated in FIG. 1, each UE 106 may also be capable of receivingsignals from (and possibly within communication range of) one or moreother cells (which might be provided by other base stations 102B-N),which may be referred to as “neighboring cells”. Such cells may also becapable of facilitating communication between user devices and/orbetween user devices and the network 100. Such cells may include “macro”cells, “micro” cells, “pico” cells, and/or cells which provide any ofvarious other granularities of service area size. Other configurationsare also possible.

In some embodiments, base station 102 may be a next generation basestation, e.g., a 5G New Radio (5G NR) base station, or “gNB”. In someembodiments, a gNB may be connected to a legacy evolved packet core(EPC) network and/or to a NR core (NRC) network. In addition, a gNB cellmay include one or more transition and reception points (TRPs). Inaddition, a UE capable of operating according to 5G NR may be connectedto one or more TRPs within one or more gNBs.

Note that a UE 106 may be capable of communicating using multiplewireless communication standards. For example, the UE 106 may beconfigured to communicate using a wireless networking (e.g., Wi-Fi)and/or peer-to-peer wireless communication protocol (e.g., Bluetooth,Wi-Fi peer-to-peer, etc.) in addition to at least one cellularcommunication protocol (e.g., GSM, UMTS (associated with, for example,WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, 5G NR, HSPA, 3GPP2CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD), etc.). The UE 106 may alsoor alternatively be configured to communicate using one or more globalnavigational satellite systems (GNSS, e.g., GPS or GLONASS), one or moremobile television broadcasting standards (e.g., ATSC-M/H), and/or anyother wireless communication protocol, if desired. Other combinations ofwireless communication standards (including more than two wirelesscommunication standards) are also possible.

FIG. 2 illustrates user equipment 106 (e.g., one of the devices 106Athrough 106N) in communication with a base station 102, according tosome embodiments. The UE 106 may be a device with cellular communicationcapability such as a mobile phone, a hand-held device, a computer or atablet, or virtually any type of wireless device.

The UE 106 may include a processor that is configured to execute programinstructions stored in memory. The UE 106 may perform any of the methodembodiments described herein by executing such stored instructions.Alternatively, or in addition, the UE 106 may include a programmablehardware element such as an FPGA (field-programmable gate array) that isconfigured to perform any of the method embodiments described herein, orany portion of any of the method embodiments described herein.

The UE 106 may include one or more antennas for communicating using oneor more wireless communication protocols or technologies. In someembodiments, the UE 106 may be configured to communicate using, forexample, CDMA2000 (1×RTT/1×EV-DO/HRPD/eHRPD) or LTE using a singleshared radio and/or GSM or LTE using the single shared radio. The sharedradio may couple to a single antenna, or may couple to multiple antennas(e.g., for multiple-input, multiple-output or “MIMO”) for performingwireless communications. In general, a radio may include any combinationof a baseband processor, analog RF signal processing circuitry (e.g.,including filters, mixers, oscillators, amplifiers, etc.), or digitalprocessing circuitry (e.g., for digital modulation as well as otherdigital processing). Similarly, the radio may implement one or morereceive and transmit chains using the aforementioned hardware. Forexample, the UE 106 may share one or more parts of a receive and/ortransmit chain between multiple wireless communication technologies,such as those discussed above.

In some embodiments, the UE 106 may include any number of antennas andmay be configured to use the antennas to transmit and/or receivedirectional wireless signals (e.g., beams). Similarly, the BS 102 mayalso include any number of antennas and may be configured to use theantennas to transmit and/or receive directional wireless signals (e.g.,beams). To receive and/or transmit such directional signals, theantennas of the UE 106 and/or BS 102 may be configured to applydifferent “weight” to different antennas. The process of applying thesedifferent weights may be referred to as “precoding”.

In some embodiments, the UE 106 may include separate transmit and/orreceive chains (e.g., including separate antennas and other radiocomponents) for each wireless communication protocol with which it isconfigured to communicate. As a further possibility, the UE 106 mayinclude one or more radios which are shared between multiple wirelesscommunication protocols, and one or more radios which are usedexclusively by a single wireless communication protocol. For example,the UE 106 might include a shared radio for communicating using eitherof LTE or 5G NR (or LTE or 1×RTT or LTE or GSM), and separate radios forcommunicating using each of Wi-Fi and Bluetooth. Other configurationsare also possible.

FIG. 3—Block Diagram of a UE

FIG. 3 illustrates an example simplified block diagram of acommunication device 106, according to some embodiments. It is notedthat the block diagram of the communication device of FIG. 3 is only oneexample of a possible communication device. According to embodiments,communication device 106 may be a user equipment (UE) device, a mobiledevice or mobile station, a wireless device or wireless station, adesktop computer or computing device, a mobile computing device (e.g., alaptop, notebook, or portable computing device), a tablet and/or acombination of devices, among other devices. As shown, the communicationdevice 106 may include a set of components 300 configured to performcore functions. For example, this set of components may be implementedas a system on chip (SOC), which may include portions for variouspurposes. Alternatively, this set of components 300 may be implementedas separate components or groups of components for the various purposes.The set of components 300 may be coupled (e.g., communicatively;directly or indirectly) to various other circuits of the communicationdevice 106.

For example, the communication device 106 may include various types ofmemory (e.g., including NAND flash 310), an input/output interface suchas connector I/F 320 (e.g., for connecting to a computer system; dock;charging station; input devices, such as a microphone, camera, keyboard;output devices, such as speakers; etc.), the display 360, which may beintegrated with or external to the communication device 106, andcellular communication circuitry 330 such as for 5G NR, LTE, GSM, etc.,and short to medium range wireless communication circuitry 329 (e.g.,Bluetooth™ and WLAN circuitry). In some embodiments, communicationdevice 106 may include wired communication circuitry (not shown), suchas a network interface card, e.g., for Ethernet.

The cellular communication circuitry 330 may couple (e.g.,communicatively; directly or indirectly) to one or more antennas, suchas antennas 335 and 336 as shown. The short to medium range wirelesscommunication circuitry 329 may also couple (e.g., communicatively;directly or indirectly) to one or more antennas, such as antennas 337and 338 as shown. Alternatively, the short to medium range wirelesscommunication circuitry 329 may couple (e.g., communicatively; directlyor indirectly) to the antennas 335 and 336 in addition to, or insteadof, coupling (e.g., communicatively; directly or indirectly) to theantennas 337 and 338. The short to medium range wireless communicationcircuitry 329 and/or cellular communication circuitry 330 may includemultiple receive chains and/or multiple transmit chains for receivingand/or transmitting multiple spatial streams, such as in amultiple-input multiple output (MIMO) configuration.

In some embodiments, as further described below, cellular communicationcircuitry 330 may include dedicated receive chains (including and/orcoupled to, e.g., communicatively; directly or indirectly. dedicatedprocessors and/or radios) for multiple RATs (e.g., a first receive chainfor LTE and a second receive chain for 5G NR). In addition, in someembodiments, cellular communication circuitry 330 may include a singletransmit chain that may be switched between radios dedicated to specificRATs. For example, a first radio may be dedicated to a first RAT, e.g.,LTE, and may be in communication with a dedicated receive chain and atransmit chain shared with an additional radio, e.g., a second radiothat may be dedicated to a second RAT, e.g., 5G NR, and may be incommunication with a dedicated receive chain and the shared transmitchain.

The communication device 106 may also include and/or be configured foruse with one or more user interface elements. The user interfaceelements may include any of various elements, such as display 360 (whichmay be a touchscreen display), a keyboard (which may be a discretekeyboard or may be implemented as part of a touchscreen display), amouse, a microphone and/or speakers, one or more cameras, one or morebuttons, and/or any of various other elements capable of providinginformation to a user and/or receiving or interpreting user input.

The communication device 106 may further include one or more smart cards345 that include SIM (Subscriber Identity Module) functionality, such asone or more UICC(s) (Universal Integrated Circuit Card(s)) cards 345.

As shown, the SOC 300 may include processor(s) 302, which may executeprogram instructions for the communication device 106 and displaycircuitry 304, which may perform graphics processing and provide displaysignals to the display 360. The processor(s) 302 may also be coupled tomemory management unit (MMU) 340, which may be configured to receiveaddresses from the processor(s) 302 and translate those addresses tolocations in memory (e.g., memory 306, read only memory (ROM) 350, NANDflash memory 310) and/or to other circuits or devices, such as thedisplay circuitry 304, short range wireless communication circuitry 229,cellular communication circuitry 330, connector I/F 320, and/or display360. The MMU 340 may be configured to perform memory protection and pagetable translation or set up. In some embodiments, the MMU 340 may beincluded as a portion of the processor(s) 302.

As noted above, the communication device 106 may be configured tocommunicate using wireless and/or wired communication circuitry. Thecommunication device 106 may be configured to transmit a request toattach to a first network node operating according to the first RAT andtransmit an indication that the wireless device is capable ofmaintaining substantially concurrent connections with the first networknode and a second network node that operates according to the secondRAT. The wireless device may also be configured transmit a request toattach to the second network node. The request may include an indicationthat the wireless device is capable of maintaining substantiallyconcurrent connections with the first and second network nodes. Further,the wireless device may be configured to receive an indication that dualconnectivity (DC) with the first and second network nodes has beenestablished.

As described herein, the communication device 106 may include hardwareand software components for implementing features for using multiplexingto perform transmissions according to multiple radio access technologiesin the same frequency carrier (e.g., and/or multiple frequencycarriers), as well as the various other techniques described herein. Theprocessor 302 of the communication device 106 may be configured toimplement part or all of the features described herein, e.g., byexecuting program instructions stored on a memory medium (e.g., anon-transitory computer-readable memory medium). Alternatively (or inaddition), processor 302 may be configured as a programmable hardwareelement, such as an FPGA (Field Programmable Gate Array), or as an ASIC(Application Specific Integrated Circuit). Alternatively (or inaddition) the processor 302 of the communication device 106, inconjunction with one or more of the other components 300, 304, 306, 310,320, 329, 330, 340, 345, 350, 360 may be configured to implement part orall of the features described herein.

In addition, as described herein, processor 302 may include one or moreprocessing elements. Thus, processor 302 may include one or moreintegrated circuits (ICs) that are configured to perform the functionsof processor 302. In addition, each integrated circuit may includecircuitry (e.g., first circuitry, second circuitry, etc.) configured toperform the functions of processor(s) 302.

Further, as described herein, cellular communication circuitry 330 andshort range wireless communication circuitry 329 may each include one ormore processing elements and/or processors. In other words, one or moreprocessing elements/processors may be included in cellular communicationcircuitry 330 and, similarly, one or more processing elements/processorsmay be included in short range wireless communication circuitry 329.Thus, cellular communication circuitry 330 may include one or moreintegrated circuits (ICs) that are configured to perform the functionsof cellular communication circuitry 330. In addition, each integratedcircuit may include circuitry (e.g., first circuitry, second circuitry,etc.) configured to perform the functions of cellular communicationcircuitry 330. Similarly, the short range wireless communicationcircuitry 329 may include one or more ICs that are configured to performthe functions of short range wireless communication circuitry 329. Inaddition, each integrated circuit may include circuitry (e.g., firstcircuitry, second circuitry, etc.) configured to perform the functionsof short range wireless communication circuitry 329.

FIG. 4—Block Diagram of a Base Station

FIG. 4 illustrates an example block diagram of a base station 102,according to some embodiments. It is noted that the base station of FIG.4 is merely one example of a possible base station. As shown, the basestation 102 may include processor(s) 404 which may execute programinstructions for the base station 102. The processor(s) 404 may also becoupled to memory management unit (MMU) 440, which may be configured toreceive addresses from the processor(s) 404 and translate thoseaddresses to locations in memory (e.g., memory 460 and read only memory(ROM) 450) or to other circuits or devices.

The base station 102 may include at least one network port 470. Thenetwork port 470 may be configured to couple to a telephone network andprovide a plurality of devices, such as UE devices 106, access to thetelephone network as described above in FIGS. 1 and 2.

The network port 470 (or an additional network port) may also oralternatively be configured to couple to a cellular network, e.g., acore network of a cellular service provider. The core network mayprovide mobility related services and/or other services to a pluralityof devices, such as UE devices 106. In some cases, the network port 470may couple to a telephone network via the core network, and/or the corenetwork may provide a telephone network (e.g., among other UE devicesserviced by the cellular service provider).

In some embodiments, base station 102 may be a next generation basestation, e.g., a 5G New Radio (5G NR) base station, or “gNB”. In suchembodiments, base station 102 may be connected to a legacy evolvedpacket core (EPC) network and/or to a NR core (NRC) network. Inaddition, base station 102 may be considered a 5G NR cell and mayinclude one or more transition and reception points (TRPs). In addition,a UE capable of operating according to 5G NR may be connected to one ormore TRPs within one or more gNBs.

The base station 102 may include at least one antenna 434, and possiblymultiple antennas. The radio 430 and at least one antenna 434 may beconfigured to operate as a wireless transceiver and may be furtherconfigured to communicate with UE devices 106. The antenna 434 maycommunicate with the radio 430 via communication chain 432.Communication chain 432 may be a receive chain, a transmit chain orboth. The radio 430 may be configured to communicate via variouswireless communication standards, including, but not limited to, 5G NR,LTE, LTE-A, GSM, UMTS, CDMA2000, Wi-Fi, etc.

The base station 102 may be configured to communicate wirelessly usingmultiple wireless communication standards. In some instances, the basestation 102 may include multiple radios, which may enable the basestation 102 to communicate according to multiple wireless communicationtechnologies. For example, as one possibility, the base station 102 mayinclude an LTE radio for performing communication according to LTE aswell as a 5G NR radio for performing communication according to 5G NR.In such a case, the base station 102 may be capable of operating as bothan LTE base station and a 5G NR base station. As another possibility,the base station 102 may include a multi-mode radio which is capable ofperforming communications according to any of multiple wirelesscommunication technologies (e.g., 5G NR and Wi-Fi, LTE and Wi-Fi, LTEand UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

As described further subsequently herein, the BS 102 may includehardware and software components for implementing or supportingimplementation of features described herein. The processor 404 of thebase station 102 may be configured to implement or supportimplementation of part or all of the methods described herein, e.g., byexecuting program instructions stored on a memory medium (e.g., anon-transitory computer-readable memory medium). Alternatively, theprocessor 404 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit), or a combination thereof. Alternatively(or in addition) the processor 404 of the BS 102, in conjunction withone or more of the other components 430, 432, 434, 440, 450, 460, 470may be configured to implement or support implementation of part or allof the features described herein.

In addition, as described herein, processor(s) 404 may include one ormore processing elements. Thus, processor(s) 404 may include one or moreintegrated circuits (ICs) that are configured to perform the functionsof processor(s) 404. In addition, each integrated circuit may includecircuitry (e.g., first circuitry, second circuitry, etc.) configured toperform the functions of processor(s) 404.

Further, as described herein, radio 430 may include one or moreprocessing elements. Thus, radio 430 may include one or more integratedcircuits (ICs) that are configured to perform the functions of radio430. In addition, each integrated circuit may include circuitry (e.g.,first circuitry, second circuitry, etc.) configured to perform thefunctions of radio 430.

FIG. 5—Block Diagram of Cellular Communication Circuitry

FIG. 5 illustrates an example simplified block diagram of cellularcommunication circuitry, according to some embodiments. It is noted thatthe block diagram of the cellular communication circuitry of FIG. 5 isonly one example of a possible cellular communication circuit; othercircuits, such as circuits including or coupled to sufficient antennasfor different RATs to perform uplink activities using separate antennas,are also possible. According to embodiments, cellular communicationcircuitry 330 may be included in a communication device, such ascommunication device 106 described above. As noted above, communicationdevice 106 may be a user equipment (UE) device, a mobile device ormobile station, a wireless device or wireless station, a desktopcomputer or computing device, a mobile computing device (e.g., a laptop,notebook, or portable computing device), a tablet and/or a combinationof devices, among other devices.

The cellular communication circuitry 330 may couple (e.g.,communicatively; directly or indirectly) to one or more antennas, suchas antennas 335 a-b and 336 as shown (in FIG. 3). In some embodiments,cellular communication circuitry 330 may include dedicated receivechains (including and/or coupled to, e.g., communicatively; directly orindirectly. dedicated processors and/or radios) for multiple RATs (e.g.,a first receive chain for LTE and a second receive chain for 5G NR). Forexample, as shown in FIG. 5, cellular communication circuitry 330 mayinclude a modem 510 and a modem 520. Modem 510 may be configured forcommunications according to a first RAT, e.g., such as LTE or LTE-A, andmodem 520 may be configured for communications according to a secondRAT, e.g., such as 5G NR.

As shown, modem 510 may include one or more processors 512 and a memory516 in communication with processors 512. Modem 510 may be incommunication with a radio frequency (RF) front end 530. RF front end530 may include circuitry for transmitting and receiving radio signals.For example, RF front end 530 may include receive circuitry (RX) 532 andtransmit circuitry (TX) 534. In some embodiments, receive circuitry 532may be in communication with downlink (DL) front end 550, which mayinclude circuitry for receiving radio signals via antenna 335 a.

Similarly, modem 520 may include one or more processors 522 and a memory526 in communication with processors 522. Modem 520 may be incommunication with an RF front end 540. RF front end 540 may includecircuitry for transmitting and receiving radio signals. For example, RFfront end 540 may include receive circuitry 542 and transmit circuitry544. In some embodiments, receive circuitry 542 may be in communicationwith DL front end 560, which may include circuitry for receiving radiosignals via antenna 335 b.

In some embodiments, a switch 570 may couple transmit circuitry 534 touplink (UL) front end 572. In addition, switch 570 may couple transmitcircuitry 544 to UL front end 572. UL front end 572 may includecircuitry for transmitting radio signals via antenna 336. Thus, whencellular communication circuitry 330 receives instructions to transmitaccording to the first RAT (e.g., as supported via modem 510), switch570 may be switched to a first state that allows modem 510 to transmitsignals according to the first RAT (e.g., via a transmit chain thatincludes transmit circuitry 534 and UL front end 572). Similarly, whencellular communication circuitry 330 receives instructions to transmitaccording to the second RAT (e.g., as supported via modem 520), switch570 may be switched to a second state that allows modem 520 to transmitsignals according to the second RAT (e.g., via a transmit chain thatincludes transmit circuitry 544 and UL front end 572).

In some embodiments, the cellular communication circuitry 330 may beconfigured to transmit, via the first modem while the switch is in thefirst state, a request to attach to a first network node operatingaccording to the first RAT and transmit, via the first modem while theswitch is in a first state, an indication that the wireless device iscapable of maintaining substantially concurrent connections with thefirst network node and a second network node that operates according tothe second RAT. The wireless device may also be configured transmit, viathe second radio while the switch is in a second state, a request toattach to the second network node. The request may include an indicationthat the wireless device is capable of maintaining substantiallyconcurrent connections with the first and second network nodes. Further,the wireless device may be configured to receive, via the first radio,an indication that dual connectivity with the first and second networknodes has been established.

As described herein, the modem 510 may include hardware and softwarecomponents for implementing features for using multiplexing to performtransmissions according to multiple radio access technologies in thesame frequency carrier, as well as the various other techniquesdescribed herein. The processors 512 may be configured to implement partor all of the features described herein, e.g., by executing programinstructions stored on a memory medium (e.g., a non-transitorycomputer-readable memory medium). Alternatively (or in addition),processor 512 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit). Alternatively (or in addition) theprocessor 512, in conjunction with one or more of the other components530, 532, 534, 550, 570, 572, 335 and 336 may be configured to implementpart or all of the features described herein.

In some embodiments, processor(s) 512, 522, etc. may be configured toimplement or support implementation of part or all of the methodsdescribed herein, e.g., by executing program instructions stored on amemory medium (e.g., a non-transitory computer-readable memory medium).Alternatively, the processor(s) 512, 522, etc. may be configured as aprogrammable hardware element, such as an FPGA, or as an ASIC, or acombination thereof. In addition, as described herein, processor(s) 512,522, etc. may include one or more processing elements. Thus,processor(s) 512, 522, etc. may include one or more integrated circuits(ICs) that are configured to perform the functions of processor(s) 512,522, etc. In addition, each integrated circuit may include circuitry(e.g., first circuitry, second circuitry, etc.) configured to performthe functions of processor(s) 512, 522, etc.

As described herein, the modem 520 may include hardware and softwarecomponents for implementing features for using multiplexing to performtransmissions according to multiple radio access technologies in thesame frequency carrier, as well as the various other techniquesdescribed herein. The processors 522 may be configured to implement partor all of the features described herein, e.g., by executing programinstructions stored on a memory medium (e.g., a non-transitorycomputer-readable memory medium). Alternatively (or in addition),processor 522 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit). Alternatively (or in addition) theprocessor 522, in conjunction with one or more of the other components540, 542, 544, 550, 570, 572, 335 and 336 may be configured to implementpart or all of the features described herein.

FIGS. 6-7—5G NR Architecture

In some implementations, fifth generation (5G) wireless communicationwill initially be deployed concurrently with other wirelesscommunication standards (e.g., LTE). For example, whereas FIG. 6illustrates a possible standalone (SA) implementation of a nextgeneration core (NGC) network 606 and 5G NR base station (e.g., gNB604), dual connectivity between LTE and 5G new radio (5G NR or NR), suchas in accordance with the exemplary non-standalone (NSA) architectureillustrated in FIG. 7, has been specified as part of the initialdeployment of NR. Thus, as illustrated in FIG. 7, evolved packet core(EPC) network 600 may continue to communicate with current LTE basestations (e.g., eNB 602). In addition, eNB 602 may be in communicationwith a 5G NR base station (e.g., gNB 604) and may pass data between theEPC network 600 and gNB 604. In some instances, the gNB 604 may alsohave at least a user plane reference point with EPC network 600. Thus,EPC network 600 may be used (or reused) and gNB 604 may serve as extracapacity for UEs, e.g., for providing increased downlink throughput toUEs. In other words, LTE may be used for control plane signaling and NRmay be used for user plane signaling. Thus, LTE may be used to establishconnections to the network and NR may be used for data services. As willbe appreciated, numerous other non-standalone architecture variants arepossible.

FIG. 8—Radio Resource Control (RRC) Messages in 2-Step Random Access

A 4-step random access (RA) procedure (e.g., random access channel(RACH)) may be used to initiate, resume, setup, or reestablish aconnection (e.g., a radio resource control (RRC) connection) between aUE and a BS, e.g., in LTE. Newer wireless standards, e.g., NR, may seekto reduce latency and/or signaling overhead by using a 2-step RAprocedure, under at least some circumstances. However, various featuresof 2-step RA procedures have not yet been determined. For example,downlink (DL) radio resource control (RRC) message transmissionprocedures are not currently resolved for 2-step RA procedures.

FIG. 8 is a communication flow diagram which illustrates exemplarytechniques for performing transmission of DL RRC messages and/or otherconnection configuration messages in association with 2-step RA. Aspectsof the method of FIG. 8 may be implemented by a network including one ormore base stations (e.g., BS 102) in communication with one or morewireless device, such as the UE(s) 106, as illustrated in and describedwith respect to the Figures, or more generally in conjunction with anyof the computer circuitry, systems, devices, elements, or componentsshown in the Figures, among other devices, as desired. For example, aprocessor (or processors) of the UE (e.g., processor(s) 302,processor(s) associated with communication circuitry 329 or 330 such asprocessor(s) 512 and/or 522, etc.), base station (e.g., processor(s)404, or a processor associated with radio 430 and/or communication chain432, among various possibilities), or network element (e.g., anycomponent of NGC 606, EPC 600, etc.) may cause the UE or base station toperform some or all of the illustrated method elements. Note that whileat least some elements of the method are described in a manner relatingto the use of communication techniques and/or features associated with3GPP specification documents, such description is not intended to belimiting to the disclosure, and aspects of the method may be used in anysuitable wireless communication system, as desired. Further, the methodmay be applied in other contexts (e.g., between multiple UEs, e.g., indevice-to-device communications). In various embodiments, some of theelements of the methods shown may be performed concurrently, in adifferent order than shown, may be substituted for by other methodelements, or may be omitted. Additional method elements may also beperformed as desired. As shown, the method may operate as follows.

A BS 102 may transmit system information about a network, e.g., acellular network, according to some embodiments (802). A user equipmentdevice (e.g., UE 106) may detect the network, e.g., based on the systeminformation. The UE may determine configuration information related toperforming random access (RA) with the network. For example, the BS maybroadcast and the UE may receive one or more system information blocks(SIB) such as SIB1 transmitted by the BS which may include the RAconfiguration information. The RA configuration information may includecondition configuration information and/or RA procedure configurationinformation, among various possibilities. The RA configurationinformation may apply to 2-step RA and/or 4-step RA.

The RA procedure configuration information may indicate resources and/ora transmission scheme (e.g., or schemes) for a downlink RRC message ormessages and/or other connection configuration message(s), e.g., whichmay be transmitted by the BS to the UE based on a successful RAprocedure. For example, the RA procedure configuration information mayindicate any of the various transmission schemes described herein, e.g.,with respect to 840 below and/or subsequent Figures.

The RA procedure configuration information may indicate resources (e.g.,time and/or frequency resources on a physical random access channel(PRACH)) for use for transmitting and receiving RA messages. The RAconfiguration may identify resources for any of various RA messages,including message 1 (Msg1), Msg2, Msg3, Msg4, MsgA, and/or MsgB.Msg1-Msg4 (described with reference to, for example, FIG. 9) may beuseful for 4-step RA and MsgA and MsgB (described with reference to, forexample, FIG. 10) may be useful for 2-step RA.

Based on the RA procedure configuration and/or other factors (e.g.,application traffic activity, measurements, etc.) the UE 106 maydetermine to perform a 2-step RA procedure and may transmit a MsgA tothe BS 102 (802), according to some embodiments. The MsgA may utilize apreamble according to the RA configuration information. The MsgA mayalso include control information. MsgA is further described below withrespect to FIG. 10.

In response to the MsgA, the BS 102 may transmit MsgB to the UE 106(816), according to some embodiments. The MsgB may include a response tothe MsgA. Such a response to MsgA (e.g., a random access response (RAR))may include: an indication of success, an indication to fallback to a4-step RA procedure (e.g., in response to MsgA being incompletelyreceived by the BS 102), and/or a backoff indication (e.g., signalingthe UE to attempt random access again). MsgB is further described belowwith respect to FIG. 10.

The BS 102 may transmit a downlink (DL) RRC message and/or otherconnection configuration message(s) to the UE 106 (840), according tosome embodiments. The BS 102 may transmit the connection configurationmessage(s) to the UE in a manner indicated in the RA configurationinformation. For example, the BS may transmit the message(s) using timeand frequency resources consistent with an indication transmitted assystem information. The UE 106 may determine the time and frequencyresources to receive the connection configuration message(s) accordingto such RA configuration information or other system information.

The DL RRC message may be an RRC setup message, among variouspossibilities. More generally, the connection configuration message mayindicate to the UE one or more parameters or settings to configure theconnection between the UE and the BS 102. The DL RRC message and/orother connection configuration message(s) may be transmitted subsequentto MsgB or concurrently with MsgB (e.g., multiplexed with MsgB), amongother possibilities.

According to various embodiments, the DL RRC message and/or otherconnection configuration message(s) may be group-cast (e.g., multiplerespective messages to corresponding respective UEs may be multiplexedtogether) or may be unicast (e.g., a message may be sent to anindividual UE using a dedicated transmission).

In the case of a unicast transmission, the DL RRC message and/or otherconnection configuration message(s) may be transmitted under any of thefollowing conditions, among various possibilities. The BS 102 maytransmit the message after receiving an acknowledgement (e.g., ACK) fromthe UE of MsgB, e.g., indicating successful reception of MsgB. The BS102 may transmit the message without (e.g., or prior to) receiving suchan ACK. The BS 102 may transmit the message according to a DL resourceassignment that may be included in MsgB or transmitted at a fixed time,among various possibilities.

In some embodiments, the DL resource assignment may be indicated in aPDCCH. The BS 102 may transmit the message at a fixed time (e.g., acertain period of time after transmitting the MsgB or a certain periodof time after receiving MsgA). For example, the time and frequencyresources used for transmission of the DL RRC message and/or otherconnection configuration message(s) may be indicated in RA configurationinformation. A unicast (e.g., dedicated) transmission of the message(e.g., according to any of the options described herein) may provide forHARQ acknowledgement (e.g., and retransmission, if needed) of themessage.

In the case of a group-cast transmission, the BS 102 may transmit themessage multiplexed with responses to MsgA included in MsgB. In otherwords, MsgB may be multiplexed with the DL RRC message and/or otherconnection configuration message(s) to various UEs. For example, eachresponse indicating successful random access may optionally include acorresponding DL RRC message and/or other connection configurationmessage. As another example, a new type of media access control (MAC)sub protocol data unit (subPDU) may be introduced to include the DL RRCmessage and/or other connection configuration message, e.g., an RRC-MsgMAC subPDU. The RRC-Msg MAC subPDU may be next to (e.g., successivelyfollow, e.g., as illustrated in FIG. 15) a corresponding response or maybe located after all responses (e.g., as illustrated in FIG. 16).

Retransmission of such multiplexed configuration messages may be handledby RACH retransmission, e.g., started from MsgA. In other words, if theUE does not successfully receive the DL RRC message and/or otherconnection configuration message, the UE may restart the RA process bytransmitting (e.g., retransmitting) MsgA. Alternatively, the UE mayfallback to 4-step RA, e.g., by transmitting Msg3.

In another example of group-cast transmission, the BS 102 may transmit adedicated MAC PDU including the DL RRC message and/or other connectionconfiguration messages for any number of UEs. For example, the BS maytransmit a dedicated RRC-msg type MAC PDU, e.g., subsequent totransmission of corresponding MsgB for the UE(s). In such a dedicatedMAC PDU any number of configuration messages (e.g., RRC-Msg MAC subPDUs)may be concatenated. Such a message may be scheduled via RA-RNTI.Retransmission may be scheduled via T-C-RNTI, e.g., as allocated inMsgB-RAR.

FIG. 9—4-Step Random Access

FIG. 9 illustrates aspects of 4-step RA, according to some embodiments.A UE (e.g., UE 106) may transmit a RA preamble to a gNB (e.g., BS 102)(902). The preamble may be referred to as Msg1 (e.g., message 1).Physical RA channel (PRACH) resource/preamble may be configured viasystem information block 1 (SIB1) or RRC dedicated signaling. Multiplepreambles may be transmitted on one PRACH resource. The UE may selectthe PRACH occasion and preamble for Msg1 transmission.

The BS 102 may respond to the preamble with a RA response (RAR) (904).The RAR may be referred to as Msg2. Msg2 may be transmitted using a RAradio network temporary identifier (RA-RNTI) associated with the PRACHoccasion in which the preamble is transmitted. In other words, the Msg2may be scheduled via a physical downlink control channel (PDCCH) withthe RA RNTI.

In some embodiments, the RA-RNTI may be calculated based on variousfactors such as: a symbol index (e.g., the index of the first OFDMsymbol of the PRACH occasion, a slot index (e.g., the index of the firstslot of the PRACH occasion in a system frame, a frequency index (e.g.,the index of the PRACH occasion in the frequency domain, and an index ofthe carrier used for transmitting the preamble. The UE may monitor thephysical downlink control channel (PDCCH) masked by RA-RNTI within a RARwindow (e.g., from the time of the transmission of the preamble). Basedon detecting its preamble (e.g., RAPID) in the RAR, the UE may considerMsg2 reception successful.

Msg2 may include: an uplink (UL) grant for Msg3, a timing advance (TA)command, and a temporary cell radio network temporary identifier(T-C-RNTI). The TA command may serve to synchronize the UE and thenetwork.

In some embodiments, Msg2 transmission may be group-cast and scheduledby RA-RNTI. In other words, the BS 102 may multiplex RAR for multipleUEs in a single message (e.g., a MAC PDU containing respective subPDUsfor each of multiple respective UEs). Thus, Msg2 may not be configuredto support retransmissions, e.g., via hybrid automatic repeat request(HARQ).

The UE may respond to the RAR with a scheduled transmission (906). Thescheduled transmission may be referred to as Msg3. The UE may transmitMsg3 according to the UL grant in the RAR (e.g., in Msg2). The UE maymonitor PDCCH masked by T-C-RNTI for potential Msg3 retransmission(e.g., for an indication from the BS to retransmit Msg3).

In some embodiments, the Msg3 may include a logical channel identifier(LCID) and a common control channel (CCCH) service data unit (SDU)and/or a media access control (MAC) protocol data unit (PDU), amongvarious possibilities.

The BS 102 may respond to Msg3 with a contention resolution (CR) (908).The CR (e.g., a CR MAC control element (CE)) may be referred to as Msg4.In some embodiments, Msg4 may also include a first DL RRC message, e.g.,in addition to the CR. In other words, the DL RRC message may bemultiplexed in Msg4.

The BS 102 may transmit Msg4 via a unicast transmission (e.g., atransmission dedicated to an individual UE). The unicast transmissionmay be scheduled by T-C-RNTI and may support HARQ retransmission,according to some embodiments. A UE may monitor PDCCH masked by T-C-RNTIand/or C-RNTI. If a CR is received the RA procedure may be a success.

The (e.g., first) DL RRC message may include any of: RRC reject, RRCsetup, RRC reestablishment, and/or RRC resume messages, among variouspossibilities. Including the DL RRC message with the Msg4 may reduce thelatency of the RRC procedure (e.g., may enable the UE to receive the RRCmessage and perform RRC configuration sooner relative to a case in whichthe DL RRC message is transmitted subsequent to the Msg4).

Following reception of the first RRC message, the UE may operate asindicated in the RRC message.

FIG. 10—2-Step Random Access Procedure

FIG. 10 illustrates an exemplary 2-step RA procedure, e.g., for initialaccess, according to some embodiments. A 2-step RA procedure may includeMsgA (e.g., similar to Msg1 combined with Msg3) and MsgB (e.g., similarto Msg2 combined with Msg4).

A UE (e.g., UE 106) may transmit MsgA to a BS (e.g., BS 102)(1002). TheMsgA may include a preamble (1004) and a CCCH MAC CE transmitted on aPUSCH (1006). The preamble and MAC PDU may be transmitted concurrentlyor sequentially (e.g., with or without a time interval in between thetransmissions) on one or more frequencies. Based on determining toperform a 2-step RA procedure, the UE may select the next availablePRACH resource, and may (e.g., randomly) select a preamble fortransmission of MsgA (1002).

After transmitting MsgA, the UE may start monitoring for MsgB within a2-step RAR window. The 2-step RAR window may be determined based onreceived RA configuration information, network configuration,definitions in a standard, etc. The BS may respond with a MsgB (1016),e.g., during the RAR window. MsgB may indicate success or fallback inthe RAR. MsgB may multiplex RAR for multiple UEs. MsgB may include aPDCCH transmitted with a MsgB-RNTI (1018) and a MsgB-MAC PDU (1020). TheMsgB-RNTI may be determined based on various factors such as: a symbolindex (e.g., the index of the first OFDM symbol of the PRACH occasion, aslot index (e.g., the index of the first slot of the PRACH occasion in asystem frame, a frequency index (e.g., the index of the PRACH occasionin the frequency domain, and an index of the carrier used fortransmitting the preamble, and potentially the PUSCH info used by MsgA.The MsgB-MAC PDU may be scheduled according to a DL grant included inthe PDCCH. The MsgB-MAC PDU may include the RAR.

In some embodiments, a SuccessRAR (e.g., an RAR indicating that the RAprocedure is successful (e.g, MsgA received successfully by the BS) andthat the UE may access the network) may include a contention resolution(CR) identifier (ID), C-RNTI, and a TA command. The CR ID may be used asan identifier for the UE, e.g., to resolve the contention(s) and assista UE in determining whether an RAR is directed to itself. In someembodiments, a FallbackRAR (e.g., an RAR indicating that the MsgA wasnot successfully or completely received by the BS, and that the UEshould fallback to a 4-step RA procedure) may include: a RA preambleidentifier (RAPID) (e.g., for the failed MsgA), a UL grant (e.g., forMsg3 transmission), T-C-RNTI, and a TA command. MsgB may additionally oralternatively include a backoff indicator (BI), e.g., to indicate to oneor more UEs to attempt MsgA again after a backoff period.

FIG. 11—MsgB

FIG. 11 illustrates a MsgB MAC PDU, according to some embodiments. TheBS may transmit a MAC PDU consisting of one or more MAC subPDUs. EachsubPDU may include a subheader indicating whether the subPDU includesbackoff indication (BI), a RA preamble (RAPID), and/or a RAR. In theillustrated example, subPDU 3 may include a MAC RAR, e.g., for a firstUE 106. MAC subPDUs 4-n may include RARs for additional UEs. Theexemplary, illustrated MsgB MAC RAR may include 13 octets. The firstoctet may include R (e.g., a reserved bit) and a timing advance (TA)command. The TA command may serve to synchronize the UE and the network.The second octet may include the remainder of the TA command and aportion of a grant, e.g., for UL and/or DL resources. The remainder ofthe grant may be included in octets 3-5. The 6^(th) and 7^(th) octetsmay include a temporary cell radio network temporary identifier(T-C-RNTI). The remaining octets may include a UE CR ID. Based ondetecting its preamble (e.g., RAPID) in the RAR, the UE may considerMsgB reception successful and may apply the timing advance value fromthe TA command for UL synchronization with the network.

FIGS. 12 and 13—Transmitting an RRC Message Using a DedicatedTransmission

FIGS. 12 and 13 are communication flow diagrams illustrating exemplaryprocesses for transmitting a first DL RRC message using a dedicated(e.g., unicast) transmission, according to some embodiments.

FIG. 12 illustrates examples in which the network sends (e.g., the BS102 transmits) the first DL RRC message via a dedicated transmissionseparate from MsgB, according to some embodiments. Transmission of MsgAand MsgB may operate as illustrated in FIG. 10 and described withrespect to 1002, 1004, 1006, and 1016 (e.g., including 1018 and 1020).

In some embodiments, the UE may transmit an acknowledgement (ACK) of theMsgB (1218), and the BS may receive the acknowledgement.

The BS may transmit the RRC message to the UE (1220). In someembodiments, transmitting the RRC message may be responsive to receivingthe acknowledgement of MsgB. In some embodiments, transmitting the RRCmessage may be responsive to expiration of a timer (e.g., the RRCmessage may be transmitted a certain amount of time after transmissionof MsgB.

Transmitting the RRC message to the UE may include transmitting a DLgrant (1222) to the UE. The DL grant may be transmitted on PDCCHresources according to T-C-RNTI. Transmitting the RRC message to the UEmay also include transmitting an RRC setup message (1224) to the UE. TheRRC setup message may be transmitted on resources indicated in the DLgrant, e.g., via PDSCH. It will be appreciated that HARQ retransmissionmay be applicable to the DL grant and RRC setup message; accordingly,1220, 1222, and/or 1224 may be repeated, if necessary (e.g., in responseto a NACK or if no ACK is received).

FIG. 13 illustrates examples in which the network sends (e.g., the BS102 transmits) the first DL RRC message via a dedicated transmissionscheduled by MsgB, according to some embodiments. Transmission of MsgAmay operate as illustrated in FIG. 10 and described with respect to1002, 1004, and 1006. Transmission of MsgB may be similar to 1016, 1018,and 1020, however a DL grant may be included in the successRAR of MsgB(1316). In other words, the MsgB-MAC PDU described above with respect to1020 and FIG. 11 may include a DL grant which identifies DL resourcesfor the first DL RRC message. The first DL RRC message may be an RRCsetup message transmitted on PDSCH resources identified by the DL grant(1318). As noted above, HARQ retransmission may be applicable to the DLgrant and RRC setup message; accordingly, retransmission (e.g., 1320,1322, and/or 1324) may occur, if necessary (e.g., in response to a NACKor if no ACK is received). It will be appreciated that retransmissionmay not be needed and may not occur in some cases.

FIGS. 14-18 Transmitting an RRC Message Using a Group-Cast Transmission

FIGS. 14-18 illustrate aspects of exemplary processes for transmitting afirst DL RRC message using a non-dedicated (e.g., group-cast ormulti-cast) transmission, according to some embodiments.

FIGS. 14-16 illustrate exemplary MAC PDUs, each including a plurality ofMAC RARs, according to some embodiments. Such a MAC PDU may betransmitted in MsgB. The MAC PDUs of FIG. 14-16 may be similar to thatof FIG. 11, in some regards. For example, each subPDU may include aheader. Further, a plurality of subPDUs may include respective RARs(e.g., indicating success or failure of the RA process) for respectiveUEs.

As shown in FIG. 14, a MAC PDU or subPDU including a successRAR (e.g.,subPDU 4, in the example) may optionally include an RRC message or otherconnection configuration message. The subheader of the subPDU mayindicate whether or not a DL RRC message and/or other connectionconfiguration message(s) is included in the subPDU. The subheader of thesubPDU may include a length indicator (LI). The LI may indicate thelength of the subPDU. Based on the LI, a UE 106 may determine whether ornot an RRC message is included in the subPDU and/or may determine thelength of the RRC message if one is included. A MAC subPDU including afallbackRAR may not include an RRC message. For example, a MAC PDU mayinclude some subPDUs which indicate successful random access attemptsand other subPDUs which indicate RA failure (e.g., fallback RAR). ThesubPDUs indicating success may include respective RRC messages and thesubPDUs indicating RA failure may not include RRC messages, according tosome embodiments.

FIGS. 15 and 16 illustrate exemplary MAC PDUs which may include new MACsubPDU types, introduced to include an RRC message multiplexed with RARin MsgB, according to some embodiments. FIG. 15 illustrates that an RRCmessage MAC sub PDU (e.g., RRC-Msg Type MAC subPDU) may be next to(e.g., may immediately follow) a subPDU with an associated successRAR.Thus, in the illustrative example, subPDU 3 may include a successRAR fora first UE and subPDU 4 may include a subPDU of a new type including theRRC message. As shown, the new type of subPDU may include a subheaderfollowed by the RRC message. In some embodiments, the subheader may notinclude the RAPID, e.g., because the RAPID of the correspondingsuccessRAR PDU may identify the UE for which the RRC message isintended. The intended UE may determine that the subPDU following itssuccessRAR is directed to it, and may therefore receive and decode theRRC-Msg MAC subPDU corresponding to its RAPID.

FIG. 16 illustrates that an RRC message MAC sub PDU (e.g., RRC-Msg TypeMAC subPDU) may follow all RAR type MAC subPDUs. Thus, in theillustrative example MAC subPDU3 may include a successRAR for a firstUE. MAC subPDU3 may be followed by any number of subPDUs containing RARsfor other UEs and/or RRC messages for other UEs. MAC subPDU n may be anRRC-Msg type subPDU for the first UE (e.g., corresponding to MAC subPDU3). The RRC-Msg type subPDU may be identified by a RAPID in thesubheader and, based on the RAPID, a UE may determine whether it is theUE for which the RRC-Msg type subPDU is intended. Any number of RRC-Msgtype subPDUs may be included in a MsgB MAC PDU.

FIG. 17 is a communication flow diagram illustrating a 2-step RA processand transmission of a dedicated MAC PDU including RRC messages for oneor more UEs (e.g., an RRC-Msg MAC PDU), according to some embodiments.Transmission of MsgA and MsgB may operate as illustrated in FIG. 10 anddescribed with respect to 1002, 1004, 1006, and 1016 (e.g., including1018 and 1020). Following transmission of MsgB, the BS 102 may transmitan RRC message MAC PDU (1730). The RRC message MAC PDU may be scheduledvia RA-RNTI. RRC messages for any number of UEs may be concatenatedtogether in the MAC PDU as illustrated in FIG. 18. For example,respective subPDUs may include RRC messages for corresponding respectiveUEs. It will be appreciated that the RRC-Msg MAC PDU may include RRCsetup messages for any number (e.g., one or more) of UEs.

A UE may consider the RA process to be a success based on receiving theMsgB, e.g., regardless of whether the RRC-Msg MAC PDU is received. Inthe event that the RRC-Msg MAC PDU is not received, a UE may requestretransmission (1732), e.g., the UE may send a negative acknowledgement(NACK). In response to such a request, the BS may perform retransmissionof the RRC-Msg MAC PDU (1734), including sending a DL grant (e.g., usingPDCCH scheduled by T-C-RNTI) (1736) and may resend the (e.g.,UE-specific) RRC setup message on PDSCH resources according to the DLgrant (1738). It will be appreciated that retransmission may not beperformed in some cases, e.g., when the initial RRC-Msg MAC PDU isreceived by the UE(s).

Additional Information and Examples

In the following, exemplary embodiments are provided.

Another exemplary embodiment may include a wireless device, comprising:an antenna; a radio coupled to the antenna; and a processing elementoperably coupled to the radio, wherein the device is configured toimplement any or all parts of the preceding examples.

A further exemplary set of embodiments may include a non-transitorycomputer accessible memory medium comprising program instructions which,when executed at a device, cause the device to implement any or allparts of any of the preceding examples.

A still further exemplary set of embodiments may include a computerprogram comprising instructions for performing any or all parts of anyof the preceding examples.

Yet another exemplary set of embodiments may include an apparatuscomprising means for performing any or all of the elements of any of thepreceding examples.

Yet another exemplary set of embodiments may include a 5G NR networknode or base station configured to perform any action or combination ofactions as substantially described herein in the Detailed Descriptionand/or Figures.

Yet another exemplary set of embodiments may include a 5G NR networknode or base station that includes any component or combination ofcomponents as described herein in the Detailed Description and/orFigures as included in a mobile device.

Embodiments of the present disclosure may be realized in any of variousforms. For example, some embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Still other embodimentsmay be realized using one or more programmable hardware elements such asFPGAs.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of the methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE 106) may be configured toinclude a processor (or a set of processors) and a memory medium, wherethe memory medium stores program instructions, where the processor isconfigured to read and execute the program instructions from the memorymedium, where the program instructions are executable to implement anyof the various method embodiments described herein (or, any combinationof the method embodiments described herein, or, any subset of any of themethod embodiments described herein, or, any combination of suchsubsets). The device may be realized in any of various forms.

It is well understood that the use of personally identifiableinformation should follow privacy policies and practices that aregenerally recognized as meeting or exceeding industry or governmentalrequirements for maintaining the privacy of users. In particular,personally identifiable information data should be managed and handledso as to minimize risks of unintentional or unauthorized access or use,and the nature of authorized use should be clearly indicated to users.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. An apparatus for operating a base station, theapparatus comprising: a processor configured to cause the base stationto: transmit random access configuration information for 2-step randomaccess; receive, from a plurality user equipment devices (UEs), a firstplurality of first messages of 2-step random access (MsgA) according tothe random access configuration information for 2-step random access;transmit, to the plurality of UEs, a plurality of second messages of2-step random access (MsgB) in response to the first plurality of firstmessages of 2-step random access (MsgA); and transmit, to the pluralityof UEs, a plurality of connection configuration messages.
 2. Theapparatus of claim 1, wherein the plurality of connection configurationmessages is multiplexed with the plurality of second messages.
 3. Theapparatus of claim 2, wherein each respective message of the pluralityof connection configuration messages is included in a respective secondmessage of a subset of the plurality of second messages.
 4. Theapparatus of claim 3, wherein the respective second message of thesubset of the plurality of second messages indicate successful randomaccess, wherein a second subset of the plurality of second messagesindicate random access failure and do not include connectionconfiguration messages.
 5. The apparatus of claim 2, wherein eachrespective message of the plurality of connection configuration messagesfollows a respective second message of the plurality of second messages.6. The apparatus of claim 2, wherein the plurality of connectionconfiguration messages follows the plurality of second messages.
 7. Theapparatus of claim 2, wherein the processor is further configured tocause the base station to: determine that a respective one of theplurality of UEs did not receive a respective one of the plurality ofconnection configuration messages; and perform a retransmission of therespective one of the plurality of connection configuration messages. 8.The apparatus of claim 1, wherein the plurality of connectionconfiguration messages is concatenated in a media access control (MAC)protocol data unit (PDU) scheduled by random access radio networktemporary identifier (RA-RNTI), wherein the messages of the plurality ofconnection configuration messages are downlink (DL) radio resourcecontrol (RRC) messages.
 9. A method for managing a base station, themethod comprising: at the base station: broadcasting system informationincluding configuration information for 2-step random access; receiving,from a first user equipment device (UE), a first MsgA; receiving, from aplurality of second UEs, a plurality of second MsgAs; transmitting, tothe first UE and the plurality of second UEs, a first MsgB that includesmultiplexed random access responses, wherein a first response of themultiplexed random access responses is for the first UE in response tothe first MsgA; and transmitting, to the first UE, a dedicated messageincluding radio resource control configuration for the first UE.
 10. Themethod of claim 9, wherein the dedicated message is transmitted afterreceiving an acknowledgement, from the first UE, of the first response.11. The method of claim 9, wherein the dedicated message is transmitteda fixed amount of time after the transmission of the first MsgB.
 12. Themethod of claim 9, wherein the first response includes a downlinkassignment, wherein the dedicated message is transmitted on resourcesindicated in the downlink assignment.
 13. The method of claim 12, themethod further comprising: determining that the first UE did not receivethe dedicated message; transmitting, to the first UE, a second downlinkassignment; and transmitting, to the first UE, a retransmission of thededicated message on resources indicated in the second downlinkassignment.
 14. An apparatus for performing random access procedures ofa user equipment device (UE), the apparatus comprising: a processorconfigured to cause the UE to: receive, from a base station, randomaccess configuration information for a network associated with the basestation; determine to perform 2-step random access; transmit, to thebase station, a first message (MsgA) of 2-step random access; receive,from the base station, a second message (MsgB) of 2-step random access;determine, based at least in part on the random access configurationinformation, first time and frequency resources associated with adownlink (DL) radio resource control (RRC) configuration message; andreceive, from the base station, the DL RRC configuration message on thefirst time and frequency resources.
 15. The apparatus of claim 14,wherein the second message includes a resource assignment, wherein thedetermination of the first time and frequency resources is further basedon the resource assignment.
 16. The apparatus of claim 14, wherein thesecond message includes a subheader including a length indicator,wherein the length indicator is useable to determine a length of the DLRRC configuration message.
 17. The apparatus of claim 14, wherein thefirst time and frequency resources are adjacent to the second message.18. The apparatus of claim 14, wherein the first time and frequencyresources are in a media access control (MAC) protocol data unit (PDU)which includes the second message, wherein one or more subPDUs arebetween the second message and the first time and frequency resources.19. The apparatus of claim 14, wherein the first time and frequencyresources are scheduled by random access radio network temporaryidentifier (RA-RNTI).
 20. The apparatus of claim 14, wherein the DL RRCconfiguration message is a retransmission, wherein the first time andfrequency resources are scheduled by temporary cell radio networktemporary identifier (T-C-RNTI).